This letter presents details of high-performance enhancement-mode GaN MIS high-electron-mobility transistor (MIS-HEMT) devices. Devices with an n-GaN/i-AlN/n-GaN triple cap layer, a recessed-gate structure, and high- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> gate dielectrics show high drain current complete operation. The maximum threshold voltage ( xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub...

Abstract In this paper, a current status and future technologies of high‐power GaN HEMTs was described. First, commercialization roadmap shown with output power efficiency status. Power electronics benchmark also introduced. Reliability improvement were addressed recent issues such as drift phenomena. Then, requirements for expanding market some device developments. Novel E‐mode recessed GaN‐HEMT has been developed using the triple cap layer structure. High‐k insulated gate Ta 2 O 5...

This letter reports on an InAlGaN/GaN high-electron-mobility transistor (HEMT) employing a SiC/diamond-bonded heat spreader with record high output power density of 22.3 W/mm. A quaternary In-added InAlGaN barrier enabled both the large current over 1 A/mm and breakdown voltage 257 V. The drain bias was increased as 100 V for S-band load-pull measurement, leading to operation. Furthermore, thermal resistance reduced by 60%, from 18.8 7.2°C/W, SiC/diamond spreader. dissipation effect clearly...

In this work, we demonstrated an excellent output power (Pout) density of 3.0 W/mm at 96 GHz using a novel collapse-free InAlGaN/GaN-HEMT with 80-nm gate for millimeter-wave amplifier. The developed devices showed basic reliability commercial products. To eliminate the current collapse, unique double-layer silicon nitride (SiN) passivation film that has oxidation resistance was adopted. We proved potential our device technology experimentally and analytically.

We demonstrated a W-band high-power-density MMIC power amplifier with 80 nm InAlGaN/GaN HEMTs. The consists of two-stage cascade units, each which has two transistors the same gate periphery for high gain and low-loss matching circuit. achieved maximum output 1.15 W PAE 12.3 % at 86 GHz under CW operation. Its density reached 3.6 W/mm, representing highest performance GaN HEMT amplifier.

The study reports the findings on a quaternary InAlGaN/GaN high electron mobility transistor (HEMT) employing thermal chemical vapor deposition (TCVD) silicon nitride (SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> ) passivation with record output power density of 31.0 W/mm in X-band. We compared two different SiN methods, namely, TCVD deposition, and plasma-enhanced CVD (PECVD) for HEMTs investigated effects device performance....

Herein, the observation of extremely high‐density (&gt;10 14 cm −2 ) 2D electron gas (2DEG) in N‐polar AlGaN/GaN heterostructures grown on sapphire substrates is reported on. Due to introducing GaN/AlN superlattice (SL) back barrier between GaN buffer layer and AlGaN layer, a giant enhancement 2DEG density observed at GaN/AlGaN interface from 3 × 10 13 (without SL) 1.4 (with SL barrier) that only one order magnitude below intrinsic crystal limit ≈10 15 . it found changes with correlated well...

Abstract An AlGaN/GaN high-electron-mobility transistor (HEMT) on a free-standing GaN substrate achieved impressive power-added and drain efficiencies of 85.2% 89.0%, respectively, at 2.45 GHz. We improved the channel quality by reducing C concentration eliminated buffer leakage path removing residual Si substrate-epitaxial layer interface. These improvements, combined with reduction in dislocation density elimination nucleation using substrate, contributed to enhanced efficiency. To best...

Machine learning–based material optimization often proceeds as a black box process, making it difficult to explain the rationale behind optimized process conditions. This study used correlation analysis and causal discovery determine amorphous silicon nitride (a-SiN) deposition parameters for GaN high-electron-mobility transistor (HEMT) devices, comparing their interpretability. To simultaneously optimize breakdown voltage, hysteresis voltage difference, sheet resistance, experiments were...

Abstract We investigated the impact of In within barriers on gate leakage current in InAlGaN/GaN high-electron-mobility transistors (HEMTs). Results revealed that (In)AlGaN depends solely two-dimensional electron gas density, regardless presence atoms. Furthermore, inclusion atoms reduces tensile strain high-Al-composition barrier, suppressing crack formation. This makes InAlGaN suitable for high-output-power HEMTs with high-Al-content barriers. Moreover, we demonstrate terminating...

An X-band transceiver frontend monolithic microwave integrated circuit (MMIC) has been successfully developed by using GaN HEMT technology. The MMIC contains a power amplifier (PA) with output higher than 19 W at 10.5 GHz, low-noise (LNA) gain of 18.5 dB and noise figure (NF) 2.3 10 an SPDT switch. fabricated occupying only 3.6 × 3.3 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> delivers 6.3 W. To the authors' knowledge, this is...

GaN-based high-electron-mobility transistors (HEMTs) fabricated on SiC substrates were successfully bonded to single-crystal diamond heat spreader by a surface activated bonding method with thin titanium (Ti) cover layer. A Ti layer the improved strength of SiC/diamond interface since formation an amorphous was suppressed. This process applied high-output power InAlGaN/GaN HEMTs spreaders. The structure reduced thermal resistance devices and enabled their high-power operation.

Abstract This paper demonstrates highly efficient GaN high-electron-mobility transistors (HEMTs) on substrates with reduced interface contamination. By applying a hydrofluoric acid-based pre-growth treatment to substrate, the Si impurity concentration at between substrate and epitaxial layer can successfully be reduced. RF performance was enhanced by owing suppression of Si-induced parasitic loss. As result, HEMTs exhibited an excellent power-added efficiency 82.8% 2.45 GHz. To best our...

Abstract In this letter, we successfully achieved high-power radio frequency (RF) operation of AlGaN/GaN high electron mobility transistors (HEMTs) fabricated on free-standing AlN substrate at X-band. The developed HEMT comprised a 200 nm thick GaN channel and AlGaN buffer with an Al composition 30%. Thanks to breakdown voltage the substrate, demonstrated 15.2 W mm −1 output power density operating voltages 70 V even without device technologies such as source-field plate optimization...

In this paper, we report a C-band power amplifier with over 340-W output using 0.8-mum GaN-HEMTs and an X-band 100-W 0.25-mum GaN-HEMTs. We used two-chip configurations the three-stage impedance transformers to extend bandwidth for both circuits. The input lines adjacent each chip are divided by four suppress non-uniform heat distribution in at high frequencies. As result, obtained 343-W 53-% added efficiency (PAE) 4.8 GHz. This is highest ever reported amplifiers. also 101-W PAE 9.8...

This paper reports on an AlGaN/GaN high-electron-mobility transistor (HEMT) free-standing AlN substrates with a record-high output power density of 24.4 W/mm at the X-band. A high-drain current operation 1.4 A/mm was realized by employing high-density 2-dimensional electron gas channel and regrown Ohmic contacts. Furthermore, high-voltage 110 V achieved owing to high-breakdown SiNx layer grown low-pressure/high-temperature chemical vapor deposition. Three-stage AlGaN buffer layers improved...

This paper presents W-band monolithic microwave integrated circuit (MMIC) amplifiers with grounded coplanar waveguide (GCPW) in 0.12μm GaN HEMT technology. A fabricated four-stage low-noise amplifier (LNA) exhibited a record gain of 23 dB at 76.5 GHz and first reported noise figure (NF) 3.8 80 for any MMIC. Another MMIC power (PA) delivered an output 25.4 dBm continuous wave (CW) operation. To our knowledge, this is the demonstration LNA as well MMICs GCPW W-band. In addition, practical...

In this paper, we describe highly reliable GaN high electron mobility transistors (HEMTs) for high-power and high-efficiency amplifiers. First, present the reliability mechanisms progress on previously reported HEMTs. Next, introduce our specific device structure HEMTs improving reliability. An n-GaN cap optimized buffer layer are used to realize efficiency by suppressing current collapse quiescent (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...

A <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">W</i> -band millimeter-wave transmitter and receiver that are based on impulse radio (IR) architecture were developed. The IR-based apparatuses have an optical-fiber input/output interface board supports multi protocol signals (OC-192 10 GbE) implements a forward error correction (FEC), enabling 10-Gb/s data transmission both in space fiber seamlessly. Analyzing model with simple on/off...

The authors have developed a highly uniform, InP-based high-electron-mobility transistor (HEMT) technology for high-speed optical communication system integrated circuits (ICs). Special attention was paid to obtaining high yield and uniformity without degrading the high-frequency characteristics of these HEMTs. An InP etch-stopper layer employed control gate recess etching. successfully fabricated InAlAs-InGaAs HEMTs with cutoff frequency 175 GHz after interconnection, which is sufficiently...

This paper presents two oscillators (OSCs) and a high power amplifier (PA) for millimeter-wave transceivers. The circuits were designed with grounded coplanar waveguide (GCPW) 0.12-μm GaN HEMT technology. One OSC, which was based on simple series source feedback topology, oscillated at frequency of 74.5 GHz an output 2.2 mW (3.38 dBm). oscillation the highest ever reported OSCs. Another OSC buffer delivered record 85 (19.28 dBm) 70.75 GHz. In addition, single-chip PA 3-stage common scheme...

We analyzed the degradation mode of GaN-HEMTs. observed sudden to make serious influence on reliability. In this paper, we proposed a new approach eliminate sudden-degradation devices. By measuring gate leakage current before stress test, can predict degradation. also discussed factor, for example, surface hexagonal pits. Using eliminating method, could select reliable devices with life over 1 times 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...

Abstract A novel piezoelectric‐induced cap structure in an AlGaN/GaN high electron mobility transistor (HEMT) was developed for enhancement‐mode (E‐mode) operation with maximum drain current density ( I dmax ), breakdown voltage BV gd ) and small collapse. Our consists of a thin GaN/AlN/ GaN triple‐layer, which reduces the sheet resistance R sh due to conduction band bending. The threshold V th is +0.25 520 mA/mm, 336 collapse by using gate recess technique. single‐chip E‐mode HEMT amplifier...